This invention relates to a structure of a junction field effect transistor.
In the conventional structure of junction field effect transistors it is well known that the high frequency characteristics thereof can be made excellent by increasing the mutual conductance thereof and decreasing the gate-to-drain and gate-to-source capacitances thereof. However, with the high resistivity semiconductor layer epitaxially grown on semiconductor substrates and including a channel region defined by gate regions, a decrease in resistivity of the epitaxial layer has caused both an increase in mutual conductance and an increase in gate-to-drain capacitance. On the other hand, an increase in resistivity has caused a decrease in gate-to-drain capacitance and also an decrease in mutual conductance. In each case, the high frequency characteristics have been deteriorated.
Accordingly, it is an object of the present invention to eliminate the objections to the prior art practice as above described.
It is another object of the present invention to provide a new and improved junction field effect transistor having excellent high frequency characteristics.
It is still another object of the present invention to provide a new and improved junction field effect transistor in which, even with a high mutual conductance, the gate-to-drain capacitance can be a minimum by applying a low voltage across a gate and a drain electrode invovlved.